Suturing member for implantable devices such as heart valves

ABSTRACT

A suturing member associated with an implantable device, as a heart valve, for accommodating sutures to join the device to living tissues. The suturing member has a porous fabric cover surrounding a semi-rigid core of plastic material. The outer surface of the plastic material is bonded to the inner surface of the fabric cover.

D United States Patent 1191 1111 3,727,240 Child 511 Apr. 17, 1973SUTURING MEMBER FOR [56] References Cited ggi i g gg SUCH AS UNITEDSTATES PATENTS 3,365,728 1/1968 Ed ard et l ..3 l [75] Inventor: FrancisW. Child, Maple Plaln, 3,464,065 9/1969 g j 3,548,417 12 1970 KischerAssigneez Medical Incorporated, Minneapolis, 3,461,869 8/1969 Hargest..3/l X Primary Examiner-Richard A. Gaudet [22] Filed: Oct. 22, 1971Assistant Examiner-Ronald L. Frinks 1 pp NO 191 617 Att0rneyRichard O.Bartz et a1.

Related US. Application Data [57] ABSTRACT [62] Division of Sen 817,988April 21 1969 Pat. A suturing member associated with an implantable 3623 211 device, as a heart valve, for accommodating sutures to join thedevice to living tissues. The suturing member [52] Us Cl 3/1 3/DIG 3128/334R has a porous fabric cover surrounding a semi-rigid [51] I A61/22 core of plastic material. The outer surface of the l 3 DIG 1plastic material is bonded to the inner surface of the fabric cover.

10 Claims, 10 Drawing Figures PATENH-ID APR 1 7 I973 sum 1 [IF 2INVENTOR. FRANCIS w. CHILD MMMA ATTORNEYS SUTURING MEMBER FORIMPLANTABLE DEVICES SUCH AS HEART VALVES CROSS-REFERENCE TO RELATEDAPPLICATION This application is a division of U.S. Patent applicationSer. No. 817,988 filed Apr. 2l, 1969, now U.S. Pat. No. 3,623,212.

BACKGROUND OF INVENTION Implantable mechanical devices, as heart valves,are used to replace natural portions of the various body organs. Thesedevices are provided with sewing members that are initially sutured tosurrounding living tissue. The sewing members have porous material totake advantage of the natural fibrosis which can occur between livingtissue and the porous material. The porous material is retained on thedevice in a number of ways. A clamp ring and wire is shown in U.S. Pat.No. 3,099,016 to hold the sewing ring on the heart valve. A stainlesssteel ring encased in porous material is used in U.S. Pat. No. 3,396,409to hold porous material on the heart valve. These'sewing rings do notjoin or bond the body or core material to the porous cover material.

SUMMARY OF INVENTION The invention is directed to a suturing member forimplantable devices and the method of making the same. The suturingmember has a cover means including biologically inert porous materialfor accommodating live tissue ingrowth or fibrosis between thetissue andporous material. The cover means surrounds a core of plastic materialbonded to the inner surface of the cover means to confine body fluidsand blood to the cover means. The plastic material does not penetratethe porous material and interfere with tissue ingrowth. The suturingmember is made by locating uncured plastic material within the covermeans. After the cover means and uncured plastic material have beenshaped into the desired configuration, the plastic material is cured tobond the'plastic material to the inside of the cover means.

An object of the invention is to provide a suturing member with aflexible core that does not collect blood and body fluids and does notinterfere with tissue ingrowth into a, porous cover bonded .to the core.Another object of the invention is to form a suturing member directly onan implantable device in a manner which eliminates blood-collectingspaces and cavities within the suturing member. A further object of theinventionis to provide a suturing member which can be formed into avariety of shapes and which can be universally applied to all types ofimplantable devices.

IN THE DRAWINGS FIG. 5 is a view similar to FIG. 4 showing the placementof the core of uncured plastic material around the cover;

FIG. 6 is a view similar to FIG. 4 showing the cover closed about thecore of uncured plastic material;

FIG. 7 is a sectional view showing the closed cover and encased core ofplastic material shaped in the curing mold;

FIG. 8 shows a modified tubular cover placed around the base of a heartvalve;

FIG. 9 is a view similar to FIG. 7 showing the filling of the tubularcover with a core of uncured plastic material; and

FIG. 10 is a view showing the filled cover of FIG. 9 placed in a curingmold to shape and to cure the plastic material.

Referring to the drawings, there is shown in FIGS. 1 and 2 a heartvalve, indicated generally at 15, having an annular base 16 with anoutwardly open annular groove 17 for accommodating a suture flixationring or sewing collar, indicated generally at 18. The collar 18 providesa means of connecting the heart valve with the heart tissue to hold thevalve permanently in operative position. The collar 18 has sufficentrigidity so that it does not flex when hydraulic pressure is exertedagainst the valve. The suturing member of the invention can be used tohold other artificial devices permanently in operative positions in aliving body or creature. Thefollowing description is limited to collar18 mounted on a base of a toroidal heart valve, as shown in U.S. Pat.No. 3,438,394. Other types of heart valves, as ball valves, disk valvesand pivoting disk valves, can be equipped with the suturing collar ofthe invention.

The heart valve 15 has an annular element 19 movable axially relative toa circular opening in the base 16 to open and close the opening in thebase. Valve element 19 is a torus having a generally elliptical shape incross section with a continuous outer peripheral surface 21 and acontinuous inner peripheral surface 22. When the element 19 is in theclosed position, a circumferential portion of the outer peripheralsurface 21 engages a circumferential seat 23 on the inside of the basesurrounding the opening.

Located along the longitudinal axis of the base 16 is a center member 24which cooperates with the valve ele- 'ment 19 to substantially close theopening in the base restricting the flow of fluid in one directionthrough the opening. Center member 24 has a generally tear drop shapeand is positioned centrally in the opening in base 16. Circumferentiallyspaced radial legs 26 and 27 rigidly support the center member 24 on thebase 16. A

. number of legs or a single leg can be used to secure the center member24 to the base 16.

An open cage 28, extended upwardly from the base, I

directs the movement of the valve element 19 and determines the openposition of the valve element. The cage means 28 comprises a pluralityof upright arms 29 having inwardly directed fingers 31. As shown in FIG.2, the fingers 31 function as stops for the valve element 19. The opencage 28 permits the valve element 19 to have free floating androtational movement between its open and closed positions.

Referring to FIG. 3, there is shown the collar 18 in assembled relationwith the base 16. Collar 18 comprises a cover 32 of porous material heldin the groove 17 with a plurality of cords or threads 33. Located withinthe cover 32 is a body or core of plastic material 34 bonded to theinside surface of the cover 32. Stitches 36 are used to secure oppositeends of the cover 32 together to form a continuous cover member. Thecollar 18 has an outwardly directed annular flange or cuff 37 providinga sewing ring for attaching the valve to the heart tissue.

Cover 32 is a biologically inert, porous material that is compatiblewith the chemicals and fluids of the body and does not deteriorate withtime. The material can be an interlaced or knitted fabric to provide amesh or spaces into which the living tissue grows in the process ofhealing to form a permanent union with the collar and the living tissueindependently of the sutures applied by the surgeon. The collar can bemade entirely of a synthetic fiber, as Dupont Teflon cloth or Dacroncloth. The cord 33 is a wrapping thread, as Nylon thread, which firmlyholds cover 32 in the groove 17. The core material 34 is a pliableplastic material in the uncured state that is compatible with with thehuman tissue and body fluids. In addition, the core material 34 issterilizable, biologically inert, non-irritating and nontoxic to thebody fluids or body tissues. On curing the plastic material, a bondbetween the inside surface or face of the cover and the plastic materialis achieved to eliminate any pockets or separation of the cover from thecore material which can collect blood and other body fluids. The corematerial is preferably a plastic material, such as Dow Corning Silastic,fluorosilicone rubber or a similar synthetic resinous plastic material.The core material cures at a relatively low temperature to a semi-rigidrelatively nonelastic plastic which retains its molded shape. The molddetermines the ultimate shape of the collar so that mitral and aorticcollars can be made with different molds.

Referring to FIGS. 4 to 6, there is shown the process of attaching andforming the suture fixation collar on the base 16 of the heart valve 15.Referring to FIG. 4, the cover 32 made into a cylinder or sleeve isplaced about the base 16. The cord 33 is wrapped about the cover 32tightly holding the cover 32 in the groove 17 of the base 16. The cordmay have a portion woven into the cover 32 to provide a positiveconnection between the cords and the cover. The uncured plastic corematerial 34, as shown in FIG. 5, is formed into an elongated roll anduniformly placed around the cover 32 adjacent to the cords 33. Theplastic core material, being uncured, is in a relatively pliable andmalleable state so that a measurable amount of material can be extrudedfrom a container or a press. Preferably, the roll of uncured plasticcore material is weighed so that a determinative amount of material canbe placed around the cover 32.

Referring to FIG. 6, the cover 32 has been wrapped around the plasticcore material 34. The end portions of the cover 32 are lapped andattached together with stitches 36. The stitches 36, located closelyadjacent to the base 16 extend all around the base.

As shown in FIG. 7, the entire heart valve with the uncured suturecollar 18 is placed within a mold 38 having a center cavity 39 joinedwith a peripheral annular cavity 41. The collar 18 is pressed into themold cavity 41 whereby the shape of the collar is changed to conform tothe mold cavity 41 to form the outwardly directed peripheral flange 37.The collar 18 is located in the mold cavity with a light force fit sothat the cover 32 is in continuous engagement with the plastic corematerial 34. The entire valve and collar 18 are retained in the moldcavity with a cover or flat plate 42. The core material 34 is cured byheating the mold for a period of time. For example, with core materialof Silastic, the mold is heated for a period of 5 minutes at 220 F.During the curing process, the core material 34 bonds to the insidesurface, or face, of cover 32 to form a continuous and permanentconnection between the core material 34 and the cover 32. This bondeliminates the spaces or cavities between the core material 34 and thecover 32. The plastic core material 34 does not penetrate the fabric ofthe cover whereby the cover retains the porous characteristic andability to have good tissue ingrowth. The plastic core material 34 beingnonabsorbent does not soak up blood or other body fluids.

After the suture collar 18 is cured, the heart valve 15 along with thecollar 18 is removed from the mold 38. The relatively low termperatureof the curing of the plastic core material 34 does not have any harmfuleffects on the metal valve base 16 or valve element 19.

Referring to FIG. 8, there is shown a modified suture fixation ring orcollar 43 mounted on the base 16 of the heart valve. Base 16 has aninwardly directed peripheral groove 17 accommodating the suture fixationcollar 43. Collar 43 comprises an annular cover 44 enclosing plasticcore material 46. Cover 44 is of a fabric material similar to thematerial of cover 32 shown in FIG. 3. The plastic core material 46 is amixture of the plastic core material 34 with evenly dispersed smallplastic threads, as Nylon or Teflon, to reinforce the plastic material.Preferably, the plastic core material is a Silastic filled with smallTeflon or Nylon threads.

Referring to FIG. 9, the annular cover 44 is a tubular fabric placed onthe base 16 in groove 17. The cover 44, being a continuous annulus, hasapproximately the same inside diameter as the diameter of groove 17. Asshown in FIG. 10, the plastic core material 46 is placed into the cover44 with an injector 47 to fill an annular cavity within the cover 44. Ameasured amount of core material is injected into the cover.

As shown in FIG. 10, the heart valve together with the collar 43 withthe uncured plastic core material 46 is placed within a mold 48 havingan annular cavity 49 of a shape outlining the final shape of thefixation collar. The shape of the cavity may be altered as required bythe final shape of the suture fixation collar. The uncured plasticmaterial, being readily deformable, conforms to the shape of the moldcavity. The collar 43 is forced into the cavity so that it firmlypositions the plastic core material 46 in surface contact with the cover44. The mold is closed with a lid or plate 51 to confine the suturingcollar 43 to the mold cavity. The plastic core material 46 is cured andbonded to the cover 44 on application of heat to the mold. The plasticmaterial 46 bonds to the entire inside surface, or face, 45 of the cover44 and does not penetrate the fabric material of the cover, whereby thefabric cover retains its tissue ingrowth capbilities.

While the invention has been described with respect to preferredembodiments of the structure and processes of forming and joining asuture fixation member to an artificial device implantable in a body ofa living creature, various changes in shape, size and materials of thesuturing member may be made by those skilled in the art withoutdeparting from the spirit of the invention. For example, cords 33 can bemetal wire and the tubular annular cover 44 can be made of a heatcurable plastic material having a high concentra tion of fibers, asTeflon fibers. This cover can surround a core material of reinforcedplastic material. The fibers carried in the cover provide cavities andspaces for the tissue ingrowth, as well as provide a reinforcing forholding the suturing collar on the artificial implantable device. Thecover may surround only a portion of the outer surface of the coreplastic material leaving a portion of the core plastic material exposed.Inserts of metal and/or plastic members and the like rigid or semi-rigidmembers, as wires, rods, tubes or cylinders can be encased or partiallyencased in the plastic core material. Portions of the inserts mayproject axially, laterally or outwardly from the plastic core materialand cover. The suturing member can be used with implantable devicesother than heart valves that are attachable to tissue and require tissueingrowth. Devices for connecting veins and arteries can be provided withthe suture fixation structure of the invention. The device may have aportion made with the suturing member, as the base of a heart valve.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

l. A heart valve comprising: a base having an annular outside portionand a passage allowing the flow of blood through the base, valve meansselectively movable relative to said base to open and close the passageto control the flow of blood through the passage, a suturing collarsurrounding the outside portion of said base, said collar havingexternal cover means including porous material for accommodating liveheart tissue to form a union between the cover means and heart tissues,said cover means having an inner surface, annular continuous meanslocated about and engaging an annular portion of the inner surface tohold the cover means in engagement with the outside portion of the base,and

heat cured core plastic material surrounded by said cover means, saidcore plastic material having an outer surface bonded only to the innersurface of the cover means and the continuous means during the heatcuring of the core plastic material.

2. The heart valve of claim 1 wherein: the annular continuous meansadjacent a portion of the inside surface of the cover means includescord means wrapped around the inside surface of the cover means forholding the cover means on the base.

3. The heart valve of claim 1 wherein: the annular continuous meansengaging an annular portion of the inner surface of the cover means is awire.

4. The heart valve of claim 1. wherein: said cover means is a plasticfabric cloth and said core material a fluorosilicone rubber plastic,said fluorosilicone rubber plastic being bonded to the fabric cloth.

5. The heart valve of claim 1 wherein: said suturing collar has anannular outwardly directed flange.

6. A suturing member connectable to tissues of a living creaturemountable on an im lantable device cornprismg: external cover means lIlCudmg porous material for accommodating live tissues to form a unionbetween the cover means and the tissues, said cover means having aninner surface, annular continuous means located about and engaging anannular portion of the inner surface of the cover means adapted to holdthe cover means on the device, and heat cured core plastic materiallocated adjacent said cover means, said core plastic material having anouter surface bonded only to the inner surface of the cover means andthe continuous means to form said suturing member during the heat curingof the core plastic material.

7. The suturing member of claim 6 wherein: said annular continuous meanscomprises at least one cord.

8. The suturing member of claim 6 wherein: said annular continuous meanscomprises at least one wire.

9. The suturing member of claim 6 wherein: the material of the covermeans is a synthetic fiber cloth and said core plastic material is afluorosilicone rubber.

10. The suturing member of claim 6 wherein: the cover means is anannular synthetic fiber cloth and said core plastic material is bondedto only the inner surface of the fiber cloth.

1. A heart valve comprising: a base having an annular outside portionand a passage allowing the flow of blood through the base, valve meansselectively movable relative to said base to open and close the passageto control the flOw of blood through the passage, a suturing collarsurrounding the outside portion of said base, said collar havingexternal cover means including porous material for accommodating liveheart tissue to form a union between the cover means and heart tissues,said cover means having an inner surface, annular continuous meanslocated about and engaging an annular portion of the inner surface tohold the cover means in engagement with the outside portion of the base,and heat cured core plastic material surrounded by said cover means,said core plastic material having an outer surface bonded only to theinner surface of the cover means and the continuous means during theheat curing of the core plastic material.
 2. The heart valve of claim 1wherein: the annular continuous means adjacent a portion of the insidesurface of the cover means includes cord means wrapped around the insidesurface of the cover means for holding the cover means on the base. 3.The heart valve of claim 1 wherein: the annular continuous meansengaging an annular portion of the inner surface of the cover means is awire.
 4. The heart valve of claim 1 wherein: said cover means is aplastic fabric cloth and said core material a fluorosilicone rubberplastic, said fluorosilicone rubber plastic being bonded to the fabriccloth.
 5. The heart valve of claim 1 wherein: said suturing collar hasan annular outwardly directed flange.
 6. A suturing member connectableto tissues of a living creature mountable on an implantable devicecomprising: external cover means including porous material foraccommodating live tissues to form a union between the cover means andthe tissues, said cover means having an inner surface, annularcontinuous means located about and engaging an annular portion of theinner surface of the cover means adapted to hold the cover means on thedevice, and heat cured core plastic material located adjacent said covermeans, said core plastic material having an outer surface bonded only tothe inner surface of the cover means and the continuous means to formsaid suturing member during the heat curing of the core plasticmaterial.
 7. The suturing member of claim 6 wherein: said annularcontinuous means comprises at least one cord.
 8. The suturing member ofclaim 6 wherein: said annular continuous means comprises at least onewire.
 9. The suturing member of claim 6 wherein: the material of thecover means is a synthetic fiber cloth and said core plastic material isa fluorosilicone rubber.
 10. The suturing member of claim 6 wherein: thecover means is an annular synthetic fiber cloth and said core plasticmaterial is bonded to only the inner surface of the fiber cloth.